This invention relates generally to injection molding and more particularly to an injection molding nozzle having a removable outer collar portion.
Injection molding nozzles having a central bore for conveying melt to a gate are well known. Usually these nozzles have an electrical heating element to provide heat for molding thermoplastic materials in a cooled mold. Alternatively they can be cooled for molding thermosetting materials in a heated mold. Each nozzle is seated in an opening in a mold with an outer collar portion having a flange portion which sits against a circular seat in the opening. Previously, as seen in the applicant's U.S. Pat. No. 5,235,737 which issued Aug. 17, 1993, the outer collar portion has been brazed on the rear end of an elongated inner portion to form a one-piece integral nozzle. While this is advantageous for some applications, it has the disadvantages that one-piece integral nozzles are relatively costly to make and the entire nozzle must be discarded if the inner portion becomes worn or malfunctions. Furthermore, inventories of complete nozzles must be maintained to provide a selection of different length nozzles.